This invention relates to the in situ diagnosis of tissue and organs through the use of interventional spectrometry.
Illumination of tissue can induce endogenous tissue fluorescence, also known as autofluorescence. The spectrum emitted by tissue autofluorescence can be characteristic of a tissue""s underlying condition. For example, when illuminated with 370 nm light, the spectrum emitted from normal mucosa differs from that of an adenoma. Tissue autofluorescence spectrometry can thus be employed to diagnose cancerous conditions such as adenoma. Other conditions that can be identified by tissue autofluorescence include arteriosclerosis.
Tissue fluorescence may be based on intrinsic properties of the tissue, or on the differential uptake of a fluorophore administered before the spectrometry is performed.
Interventional tissue autofluorescence spectrometry is known in the art. Currently known devices locate the spectrometer at the proximal end of the interventional device, i.e. outside the patient. These devices rely on fiber optic bundles to transmit light between the analysis site and the externally-located spectrometer. The limitations inherent in employing fiber optic bundles are threefold. First, they are expensive. Second, they are stiff, lacking flexibility and maneuverability. Third, they are large, requiring a relatively large diameter to transmit the necessary amount of light to and from the analysis site. Currently known interventional spectrometry devices are thus limited to use in relatively large and straight passages, such as the gastrointestinal tract.
This invention relates to an interventional device with a spectrometer at its distal end. The spectrometer can be used to perform an in vivo analysis of a tissue""s fluorescence characteristics, which can be used in diagnosing conditions such as cancer.
It is an object of this invention to place a spectrometer at the distal end of an interventional device with a small enough form factor to be useful in diagnosing a large variety of tissues and organs in situ.
It is a further object of this invention to provide a means of communication between the distal and proximal ends of the interventional device that is flexible and narrow, thus allowing the device to be used in a variety of passageways throughout the body. It is a further object of the invention that the means of communication be inexpensive, such as a copper wire.
The spectrometer comprises a source unit for emitting light at a certain frequency or a plurality of frequencies. The spectrometer further comprises a plurality of sensors for measuring light at a plurality of frequencies.
The source unit comprises a light source. The light source can be monochromatic or polychromatic. In one embodiment, a tungsten-halogen light is employed as a polychromatic light source. If a polychromatic light source is used, a bandpass filter may be attached. The bandpass filter may allow one or more frequencies to pass through. The frequencies emitted by the source unit are selected to provide data diagnostic of a tissue""s condition. In one embodiment, the source unit emits light at a frequency of 435 nm. In other embodiments, the source unit may emit light at a frequency of 420 nm, 490 nm, or any combination thereof.
Similarly, the frequencies measured by the sensors are selected to provide data diagnostic of a tissue""s condition. In one embodiment, the spectrometer comprises two sensors, which measure light at wavelengths of 370 nm and 440 nm, respectively.
Another object of this invention is to minimize the waste heat generated by the spectrometer. In one embodiment, the source unit emits 200 xcexcw or less. In another embodiment, the surface of the distal end of the interventional device does not exceed a temperature of 40 degrees Celsius after 30 seconds of continuous operation. In one embodiment of the invention, the source unit is activated in brief pulses in order to keep heat down to a minimum.